A mobile workbench which travels on a subject cutting material such as a steel sheet or a stainless steel sheet and cuts the subject cutting material by operating a gas cutting torch or a plasma cutting torch installed therein has been used. Alternatively, a mobile workbench which travels on one side of a subject welding material such as a pair of steel sheets or stainless steel sheets and welds the subject welding material by operating the welding torch installed therein has been used.
In the case of the above-described mobile workbench, plural wheels are arranged, and a cutting torch or a welding torch is generally disposed between the wheels disposed at the front and rear sides in the traveling direction, so that a desired process may be performed within a limited area. That is, the position where the wheel of the mobile workbench approaches a position closest to the end of the subject processing material becomes the limit.
The mobile workbench may be operated in a manner such that a worker operates switches provided in the mobile workbench. Alternatively, a teaching operation may be performed in a manner such that a worker grips a hand holding type remote operation panel constructed through a cord like a teaching and playback type mobile workbench and operates switches provided in the remote operation panel.
In particular, in the case of the mobile workbench which travels on the upper surface of the subject processing material and performs cutting or welding thereon, one worker may perform a desired process while being in charge of several mobile workbenches. In such a case, generally, the worker operates one mobile workbench so that the mobile workbench automatically travels afterward, and prepares the other mobile workbenches to operate while the first mobile workbench is automatically traveling so as to perform a process thereof.
For example, Patent Literature 1 discloses a traveling workbench (a mobile workbench) in which a guide roller travels while coming into press-contact with a surface of a steel sheet disposed perpendicularly by directing the traveling direction toward the steel sheet disposed to be slightly perpendicular to the welding proceeding direction so that the surfaces of the steel sheets disposed to be perpendicular to each other are used as a guide when the intersection portion between two steel sheets (the subject processing materials) disposed to be perpendicular to each other are fillet-welded. In the case of using the traveling workbench, welding may be satisfactorily performed by using upright plates as a guide.
However, even in the traveling workbench with the above-described configuration, it is a problem to stop the traveling workbench when it reaches the end of the steel sheet. In order to solve this problem, a traveling workbench is proposed which is stopped in accordance with a detection signal generated when the end of the steel sheet is detected by a sensor installed in the traveling workbench or a dock provided near the end of the steel sheet is detected by the sensor.